Contribution of the LIM domain and nebulin-repeats to the interaction of Lasp-2 with actin filaments and focal adhesions

PLoS One. 2009 Oct 23;4(10):e7530. doi: 10.1371/journal.pone.0007530.

Abstract

Lasp-2 binds to actin filaments and concentrates in the actin bundles of filopodia and lamellipodia in neural cells and focal adhesions in fibroblastic cells. Lasp-2 has three structural regions: a LIM domain, a nebulin-repeat region, and an SH3 domain; however, the region(s) responsible for its interactions with actin filaments and focal adhesions are still unclear. In this study, we revealed that the N-terminal fragment from the LIM domain to the first nebulin-repeat module (LIM-n1) retained actin-binding activity and showed a similar subcellular localization to full-length lasp-2 in neural cells. The LIM domain fragment did not interact with actin filaments or localize to actin filament bundles. In contrast, LIM-n1 showed a clear subcellular localization to filopodial actin bundles. Although truncation of the LIM domain caused the loss of F-actin binding activity and the accumulation of filopodial actin bundles, these truncated fragments localized to focal adhesions. These results suggest that lasp-2 interactions with actin filaments are mediated through the cooperation of the LIM domain and the first nebulin-repeat module in vitro and in vivo. Actin filament binding activity may be a major contributor to the subcellular localization of lasp-2 to filopodia but is not crucial for lasp-2 recruitment to focal adhesions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / chemistry*
  • Animals
  • Carrier Proteins
  • Cytoskeletal Proteins
  • Focal Adhesions / chemistry*
  • Glutathione Transferase / metabolism
  • Green Fluorescent Proteins / chemistry
  • LIM Domain Proteins
  • Mice
  • Microfilament Proteins / chemistry*
  • Microscopy, Fluorescence / methods
  • Models, Genetic
  • Muscle Proteins / chemistry*
  • Neurons / metabolism
  • Protein Binding
  • Protein Structure, Tertiary
  • src Homology Domains

Substances

  • Actins
  • Carrier Proteins
  • Cytoskeletal Proteins
  • LIM Domain Proteins
  • Microfilament Proteins
  • Muscle Proteins
  • NEBL protein, human
  • nebulin
  • Green Fluorescent Proteins
  • Glutathione Transferase